A spokesman for Northrop Grumman Corp., which built the satellite, said Monday: "This is a classified mission".

Lawmakers said they will receive classified briefings on a secret USA government satellite that apparently crashed into the sea after it was launched by Elon Musk's SpaceX.

"There's a long tradition of not commenting on problems with classified missions, unless it blows up in such a way that everyone can see it", John Logsdon, founder and former director of the Space Policy Institute at George Washington University, told Bloomberg News. "If we or others find otherwise based on further review, we will report it immediately", SpaceX Chief Operating Officer Gwynne Shotwell said in an emailed statement. "And that would put them as responsible on whether it separated from the second stage". Both the Wall Street Journal and Reuters quoted unnamed officials as saying the satellite did not separate from the Falcon 9 second stage.

SpaceX, however, never officially confirmed mission success. "We can not comment on classified missions". Few details about the satellite are officially known besides its codename "Zuma", not even which government agency meant to use the satellite nor for what objective.

Rep. Mike Rogers (R-Ala.), who heads the House Armed Services Strategic Forces subcommittee, said in a statement Wednesday that "space is a risky business" but his panel remains "committed to providing rigorous oversight that accounts for that risk and ensures that we can meet all of our national security space requirements as the Air Force looks to competitively procure space launch services in the future".

Billionaire Musk, who founded the Hawthorne, California-based SpaceX, has since hailed the milestone as a savings deal for the space industry. For most SpaceX launches, the company provides the payload adapter - that's the piece of hardware that connects the satellite to the rocket.

"The most important issue here is whether the Pentagon will rethink its reliability as a provider of launch services", said Thompson, whose think tank receives funding from Boeing and Lockheed. It did stream the successful landing of the Falcon 9 first stage rocket booster after it completed its primary mission.

On its website, SpaceX says it has more than 70 upcoming missions on its launch manifest, which could take several years.

Last year was a banner year for the private space company with 18 launches.

According to Shotwell, data already reviewed has showed that "no design, operational or other changes are needed" that would impact further launches.

The massive Falcon Heavy, which has already been staged on a Cape Canaveral launchpad, stands 230 feet tall and consists of three Falcon 9 first-stage cores.

The fact that SpaceX says the Falcon Heavy launch will move forward as scheduled also indicates there were no issues with the rocket.